Telephone-exchange system.



W. W. DEAN. TELEPHONE EXCHANGE SYSTEM.

P atented 0ct.'6,19'()8. Z SHEETS-SHEET 1 APPLIOA TIOH, FILED 00T.18, 1906.-

ZUzZ n esses;

mew-W APPLIOATIOH FILED OCT. 18, 1906.

Y W. W. DEAN-.' TELEPHONE EXOHANGE SYSTEM.

Patented Oct. 6,1908

2 SHEETS-SHEET 2.

Inventor w amm v wpem jlltbrngs WILLIAM w. DEAN, OF ELY'RIA, 01110, ASSIGNOR .TO THE DEAN ELECTRIC COMPANY, or

ELYRIA, OHIO,'A'CORPORATIQN OF OHIO.

TnmPnoNE-nxcnimen sys rnm,

' Specification of Letters Patent.

Patented a. 6, 1908.

Application filed October 18,1906. Serial No. 339,476.

To all whom it may concern."

Be it known that I, WILLIAM 'W. DEAN, a citizen of the United States, residing at Elyria, in the county of Lorain and State of tems, 9f which the f0 n the commercial practice of telephonythere are a number of conditions to be met in regard to ringing wanted subscribers, which have not heretofore been satisfied.

' 'Amon these I may mention the necessity for ma king the operators work as simple as possible, substituting mechanism in her place Whereverpracticable, so that said mech': anism will perform required operations upon her manu'al initiation; also the economic condition resulting, from raising the standards of exchange construction, and particularly that of the net work of wires and cables in a a system, so that the increase in .the investmentdemands the maximum use of the plant at a fixed rate of return, or the maximum rate of return at a fixed use, 1n order to be profitable, this condition having brought about the general adoption and use of party-'- lines in citles. Party-line ringing is inmany respects a problem by itself, but in my pres- ,ent development of the subject'l apply the same principles in its treatment which I employ in ordinary single-party orother ring-' mg, combining therewith the special feature of selection on the part of the operator.

The principal ob ect of.my invention is to meet the requirements I have stated, as Well as others included in the same category, and in so doing to produce apparatus and circuits for automatic ringing which will be ap plicable to existin systems as well as new installation, and w ich for that purpose can be made complete and self'- contained in themselves, H

A corollary object'is the elimination of inductive resistance or other impeding factor in the ringing circuit, and. the general improvementof the samein detail.

In attaining-my obi 'ects'l employ as the basis for myscheme uo circuits and ap arat-us, a ringing jrelayl' 'The operation 0 this ringing relay is the same whether it be user forsingle-party lines or for poly-station signaling. It is first energized y the act of the operator, and when energized it performs the important functions of the common ringing keyfopening the'cord circuit, and connecting the generator circuit across the terminals of the calling plug. Inconnection with this relay I provide a device responsive to current changes in the subscribers line, this device maintaining the relay circuit in operative condition, and the relay active, until the subscriber has answered, whereupon the relay is instantly disconnected and the talking circuit thereby restored, clear of all generator connections. This device preferably consists ofa loose-leaved condenser associated with an induction coil having a low wound primary. It takes current either from the generator circuit or from the main battery,

and the connections are such that it will respond as soon as the subscriber answers,

whether the generator is that moment con-- nected, or whether it is during aninterval between rings, the battery being then connected. This will be understood when I point out that I preferably employ acommutator in -the generator circuit, which putsringing current on the keys at brief recurring inter vals of say two seconds" duration, with intervening intervals of-four seconds during which the circuit is grounded, current then coming back overthe s ubscribcrs line from the main battery.

In party-line ringing, as in single station line work, the operator simply depresses the proper key, which closes t is circuit of the ringing locking circuit'through the normally closed contact of the static relay, whose primary is included between the generator circuit and the line. Generator current then goes to line at successive intervals, as already stated, until the subscriber answers, when thcstatic relay breaks the locking circuit, the ringing .relay lets 0, all enerator connections. are

cut off; an, the talking circuit is restored.

My invention is illustrated in the accompanying drawings, in which Figure l his a diagram showing two subscribers lines, one having four subscribers stations connected thereto, and a central office e uipment for interconnecting the lines, inclu ing my improved ringer devices. F1 2 is a longitudinal section showing the way in relay, which in turn closes its own '5 Referring now to .Fig.. 1, I haye shown;

therein two subscribers" stations, A, A, each connected to the central oflic'e byline-wires 1 and 2,. terminating in the contacts of a cutoif relay,-- and connected when its'relay is 10 energized to the respective jacks, J, J Each line has a lam' signal, 11, governed by the relay-in the usual way, andboth lines. are I supplied with current for-all purposes from the common mainbattery B. To interconnect these lines I show a cord-circuit 3, t, 5 6, 7 ,.8,'separated by condensers,-C, C, and cprovidedwiththe usual s ervisory signals controlled by relays, S, S, S These relays are bridged across the respective ends of 2 the'cord circuit in pairs, with the battery B between them, The conductors 34 terminate in the answering plug P, while the conductors 5'7 and 6-8 terminate in-the .calling plug P.- The combination key K and the ringing relay K are associated with this plug P Also associated with the plug is a static-relay orcircuit controller R.

- One form of static relay which I ma use' as shown in Fig. 2, comprises a loose-leacon- 30 box C upon which the contact springs S and S, and terminals S and S are mounted, somewhat after the fashion of those on an ordinary magnetic relay. The lower contact.

35. springs S and-S are normally together, the

spring S beinglonger than the other and havin its end overlying the upper end of a shoul ered stud S which rests upon the lid of the box with its shank exteridin through and-held therein to en age is e condenser. It iswell known that ing charges are imparted to the leaves of a condenser, the mutual attractive and repulsive 'forces which are set up, cause the leaves to flutter unless they 'are' suitably confined. In those condensers used merely for transmission of. alternating currents, it is customary to use heavy pressure-so as to bring the. leaves mto 1ntnnate relatlon, whlch 1s ma1ntainedby fitting the structure into a tight and rigid receptacle. In the present case -I 1 may securethe leaves of my condenser at the 1 ends or at any other suitable point or oints which will enable their relative latera positions to be maintained, and prevent the displacing ofthe interposed insulating sheets, which may be of parafiined paper or any other suitable material. The alternative sheets throughout are connected, one set of sheets being. oined to the terminal S and the other to theterminal S as indicated in 'the.

diagram of Fig. 1. When the alternating current is sent across these terminals through the condenser, these leaves being unconfined,

' 7 615 will swell and subsidewith considerable agdenser C inclose'd within a suitable casing or down en alternatgregate am litude of movement. This movement li ts the stud S and so lifts the upper sprin S and breaks the circuit therethrough. I t will'be understood that this deseriptlon ofa suitablestatic relay for my purpose is merely tentative asnumerous other tylpes might be substituted without any 0 ange in the invention, which relates more particularly to the system rather than to the structure of the condenser, although I shall claim the latter as novel.

.It will, of course, be understood that it is not necessary to employ'the induction coil shown in Fig. 1, since the condenser might be included directly in'the rin ing circuit in place of the primary of the in uction coil; as

shownin Fig. 3. In this figure the circuit connections shown in Fig. 1 are reproduced except that the condenser terminals are con nected directly with wire 1* and wire 9, all

of the other circuit connections remaining the same. Only a portion of the complete circuit shown in'Fig. 1- is shown in Fig. 3, it

being understood that the circuit connections not indicated are identical with those shown in Fig. 1. It isbetter', however, to have an induction coil, because potentials of the alter nating'current can then be step ed up, the

higher pressure thus obtained eing more suitable forlworking the condenser than the relatively low potential of the ringing cur rent Another advantage of the induction coil oi transformer is that the primary can be made low-wound with comparatively few turns, so that it will offer verylittle resistance to the current passin through it. A condenser connected direct y in any circuit always offers a certain amount of retardation and in order to avoid this, a low-wound primary is preferably used.

As shown in Fig. 1, the circuit controller R comprises an induction coil whose primary 1' is connected directly in the ringing circult by the wire 7" and the secondary r of the in- "the res ective sets of sheets of the condenser C T e secondary r is electrically disconnected from everything else except the condenser C but the primary 7 forms a part of the common generator circuit 910 passing to the key K, and having branches to all the s rings k is, k, k. The relay K is in-' c uded in a circuit, 11, 12,13, 14, 15,.passing through-the springs, 70", k. This circuit is closed, from the main battery to ground, 1.20 when any. one of the plungers is pressed all the-way downso to close together the springs, k", k. As soon as the relay attracts its armatures, owing to this closure, it locks itself through the sup )lementa'l circuit, 16, 17, 18, which asses t hrough normally closed contacts of t 1e static relay R. I have shown the station A equipped with a ringer Q, and the station A with a ringer Q.

duction coil has its terminals connected to 110 tions connected across the same circuit, 1-:2,

as the station A.

, Any. one ofthe ringers Q, Q QZQ may be operated by sending out toline a current of the proper frequency vide four generators or other sourcesof cur-Q rent, connected to the four wires 19, 20,- 21"v since all the ringers are wound'in a manner well understood 111 the art. nish proper currents for thisv selection, I pro.

and .22, leading to the four plunger springs in the key K. I have shown'bu't one of these. sources of current, marked G, and connected from ground to the wire 22- through the constantly driven'commutator G,.whicl1 has a segment insulated for the generator and the rest of its periphery grounded. The proportions of the grounded and generator segments may be. varied at'will, but theyarepreferably such and the speed of revolution is so adjusted, that the source of Cu1l8Ii't, -G, will be connected to the Wire 22 for. two seconds, and the wire'will be grounded for 21 and being taken off from the different commutators to the various keys at the'dif- :ferent operators" positions. 7

The operation of the system thus described is as follows: Assuming SUbSCI'lbEPA, to have called, and the call to-have been answered in the usual way, also that the calling plug P has been inserted in the jack J of the wanted line, if the wanted line is a single- 2party line, the operator closes the, springs .7, k, by de ressing a plunger, whereupon the relay K becomes energized by current from the main battery B, and draws in-its armatures, as shown in Fig. 1, thereby open' ing the cord conductors 5+7 and 6-8, and connecting the portions 7 and 8 to the wires 9, 11, respectively. The'wire 9 thus leads from the tip of the plug through the Wire 1' to wire 10, to key K, to generator, and ground; on the other side the wire 8 goes to main battery through the resistance r.

The locking circuit .fO TQH EZ-reIay 'K. is as .follows; 13,11, .12, K, 13, 1 8, r, .17, 16,

' ground. As long as the static relay remains in normal condition the relay K would therefore remain energized, maintaining the generator connected to the wanted line. It will be observed that so far as single arty ringing is concerned. all of the springs in 19, k 10 1c could be done away with, a single pair of springs being substituted therefor, ,to connect a single generator to the wire 10. When the called, subscriber answers, .his telephone T, becomes bridged across the line 1- 2 in place of his ringer (1% thus substitut-- ing a low resistance for a re atively high one and thereby permit-ting a very large increase in the generator current flowing in the line;

In order to furto actuate a sul;-scribe1-s ringer, as limitedby the resistance thereof, is insu'flicient to expand the condenser C enough to break thecontact springs S and S. When the subscriber has bridged his telephone, the consequent increase in current through the primary 1 throws a highpotential current through the condenser C from the secondary r, so that it expands and causes the plug 5 to press the spring S away from the spring S,

thereby opei'iing the normally closed contacts and breaking the circuit 16, 17, 18. As soon as this is brokeinthe relay K releases its armature and cuts oil" the generator, at thesame time restoring the continuity of the cord conductors. It will, of course, be under stood that the operation of a single party line will be substantially identical with the one just described with the exception that I the ringing key K would only have one set ofcontact springs.

I am aware that many changes maybe made in-the apparatus and some changes in the circuits, which I have lierein set forth,

.without, altering the characteristic essential features of my ention, and all such changes are contemplated by me and are liOr be taken as within the scope of my claims.

Having thus described my invention, what I claim and desire to secure by Letters Patout is: 1. In a telephone exchange system, an operators' cord circuit and calling plug, a ring.

ing relay adapted to connect the generator to .line, nd a static relay contro-lli'ng the ringing relay.

2. An automatic ringing device for telephone systems, comprising a ringing relay having inc-and generator connections, an 0 eratorskey adapted to rr flomentarily c ose @he relay circuit,'short circuit contacts controlled by the relay so that when energized it will lock itself, and statically open ated means controlled by the'wanted subscribertobreak the relay locking circuit.

3.111 a telephone system, a' cord circuit automatic ringing device comprising a ringingrelay, an operators keyfadapted to temorarily close the circuit of said relay, a ocking circuit closed through itself by the relay when energized, and statically operatedmeans then becoming associated with the wanted subscribers line circuit, adapted to break said lockingcircuit when the subsc'riber'removes his telephone;

4'. In a telephone system,.a cord circuit automatic ringing device comprising a ringmg relay, agenerator circu t adapted to be connected to line, a locking circuit'closed by the relay through itself when energized, statically perated means for breaking the locking circuit, and-means included in the generarated means.

I i p tor circuit adapted ,to-control said statically The static relay R'is soproportioned and ad o ecjusted that the amount of current required '1" In a telephone system, a cord circuit &

connected thereby-to line, a locking circuit an operators ringing 'ksyfor" connecting a controlled in the use of said ringing key for erators cord circuit and ca 'ng plug, a ring- I ing rela associated'with said .cord' plug and generator to' saidgenerator circuit, means energizing the relay, a locking circult for the denser.

connected thereby to line, a locking circuit 'sponsive means for breaking the locking circuit, and a manual ke under the control of l the operator for'initia y closing the circuit of the ringing relay.

' 7. In a telephone exchanfipnsystem, an operators cord circuit and ca g plug, a ringautomatic ringing device comprisingaainging relay, a generator circuit adapted to be for said relay closed by itself when ener ized, means responsive'to an act of the calle sub: scriber, static means associated with: said re-' ing rela associated with said cord plug and ad apte to. connectgeneratoi' circuit thereto,

generator to said generator circuit, means energizing the rela ,and a current responsive static device t ereafter included in the ringing generator circuit and controlling'said relay." v 1-.

8. In a telephone exchan e system, an op:

adapte to connect generator circuit thereto, an operators ringing key for connecting a" controlled in the use of said'ringin keying relayja static condenser for breaking the locking circuit, and a current responsive de- .vice thereafter included in the ringing'generator circuit and controlling said static con' erators cord circuit and calling plug, a generator, a ringing'relay associated with said cord plug an adapted to connect generator vcircuit thereto, an operators ringing key for connecting a generator to said generator circuit, means controlled in the use of said. ring-' ing key for ener izing the relay, a locking circuit for the re ay, a static condenser for breakin the locking circuit, andan induction coi thereafter included in the ringing generator circuit and responsive to an act on the part of the called subscriber for operating said static condenser.

10. In a telephone system, automatic ringing means comprising a ringing relay, a generator ada ted to be connected thereby to line, a locking circuit closed by the relay thro i h itself when energized, contacts for breaking thelocki means responsive o y to current of large volume in the line as determined by the act of the called subscriber, for opening said contacts. 1 v g 11. In a telephone system, connective means, and associated automatic ringing means com rising a ringing relay, a generator adapte to be connected thereby to line, a locking circiut closed by the rela through itself when'energized, normally c osed concircuit, and static 'tacts in the locking circuit a loose leaf cdndenser adapted when highly charged to expa'nd and open said contacts, means included in the enerator circuit for producing a large potent al difference across said condenser,

answering to augment the amount of current in the circuit, without loweringthe potential. In testimony in presence of two witnesses.

I WILLIAM W. DEAN. Witnesses: v

' M. E. Muss,

9. In a telephone exchange system, an op M. W.- ZEMAN.

andv means controlled by the subscriber inwhereof I affix my signature 

